In recent years, the usage of articulated robots (manipulators) is increasing, and the articulated robots have a wider range of applications to fields in which robots need to flexibly operate, such as work in corporation with humans or assembly work in factories.
Such a robot needs stable and wide force control (compliance control) to follow an external force. For the force control, a system that is based on torque control (torque servo) of joints is preferably formed instead of a system that has been widely used and that is based on position control (position servo) of joints. Accordingly, there is a need for a driving mechanism that accurately detects torque that acts on each joint with a sensor (torque sensor) for detecting the torque.
The structure of a typical robot includes links that are connected to each other with joints so that the robot can make various movements. Wiring members, such as electrical wires through which power or electrical signals are transmitted to actuators or sensors that are disposed on the respective joints, and an electrical wire or a pipe for driving an end effector that is mounted on a distal end portion of the robot arm, need to be disposed between a proximal end portion of the robot arm and the distal end portion. The wiring members are disposed across the joints that move a great distance. For example, PTL 1 discloses a robot arm that includes a cable holder for fixing a wiring member that extends substantially linearly over the entire cable holder.